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  <title>Document</title>
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  <script>
    function fn(params) {
      params.header = {
        // 先把之前的header 数据 解构出来
        ...params.header,
        auth: 'token',
      }
      // console.log(params)
      // params.header.auth // undefined
    }
    fn({
      url: 'aabbcc',
      header: {
        a: 1,
        b: 2,
      },
    })
  </script>
</body>

</html>